In forms of construction, patterns may be divided into three varieties, viz., (1) solid patterns, (2) hollow and skeleton patterns, and (3) sweeps.

Small patterns are built solid, made up in most cases of parts so glued together as to prevent warping. Some large patterns are also made solid for rigidity. Hollow and skeleton patterns and sweeps are made to save expense.

Fig. 115. - Steam Nozzle.

Large hollow patterns may be built up of segment work or stave work as shown in W and X, Fig. 107.